1. Field of the Invention
This invention relates to oxo-derived fatty sulphate or fatty ether sulphates in mild surfactant blends. Primarily these are anionic surfactants derived from alcohols prepared by an oxo-process. The surfactants include lauryl sulphate or lauryl ether sulphate, ether carboxylate, and lauryl ether sulphosuccinate.
2. Prior Art
Natural and synthetically derived anionic surfactants are old and well-known in the art. Indeed, compositions containing the reaction products of ethoxylated anionic surfactants and certain specific amphoteric surfactants and polyethoxylated nonionic surfactants have been disclosed in U.S. Pat. Nos. 2,999,069 and 3,055,836. Maskey and Poirier, respectively. In addition, carboxylated surfactants in shampoo and hair care formulations are also disclosed in the article Cosmetic and Toiletries, Page 99, by M. A. Esposito, K. F. Shoney, and B. A. Shukowsky, East Hanover, N.J., Volume 96, July 1981. The carboxylated surfactants of this article are effective surfactants. As detergents, their surface tension lowering properties are the same order and magnitude as more common anionics and it can be demonstrated that these carboxylates retain their surface active properties over a wide pH range. In their role as lime soap dispersants, the alkyl carboxylates perform to a degree that seems to have pushed the standard methodology to the limit. Findings on commercial products, as well as some new laboratory products, show as a class the carboxylates as effective LSD's in the range of 5% or less.
The Esposito article differs from the present invention in that the carboxylated surfactants of Esposito are seen for use in cationic systems. No discussion is had of combining them with other surfactants to provide the mild anionic surfactant blend of the present composition which is useful in substituting the less expensive synthetic versions of naturally derived surfactants. Accordingly, the present invention differs from and is not obvious in view of the Esposito article.
Combinations of sulphates, or ether sulphates with ether carboxylates have been disclosed, especially for shampoos, in GB-A-874.186, wherein it has been shown that this kind of composition possesses various synergistic actions. In NL-A-8402578 it has been shown that already at low percentages of ether carboxylate a large effect on the tolerance for hair and skin is obtained. These do not refer to the current invention which specifically embraces OXO-derived (ether) sulphates.
Bolich et al., U.S. Pat. No. 3,928,251, depicts a mild shampoo composition comprising specific ethoxylated anionic surfactants with specific Zwitterionic surfactants and polyethoxylated nonionic surfactants. Bolich differs from the present invention in that the fatty ether carboxylates, and specifically, the sodium laureth N-carboxylate surfactant, is not included in a mix as to make the composition unexpectedly mild and function well in anionic systems. Accordingly, the present invention differs from and is an improvement over Bolich.